import numpy as np
a=np.array((1,2,3),dtype=int)

print('a.dtype:',a.dtype)
print('a:',a)
b=np.array([[1,2,3],[4,5,6]])
print('b:',b)
print('b.ndim:',b.ndim)
print("n.shape:",b.shape)
print("b.size:",b.size)